This project examines the influence of psychological variables on pain, medication-use, and recovery of surgical patients whose pain is treated with periodic, intramuscular injections (IM) or patient-controlled intravenous infusion (PCA) of narcotic analgesics. Under-treatment of pain and over-sedation of patients often accompany traditional IM dosage regimens. In PCA dosing, a pump infuses a small dose of narcotic analgesic directly into the patient's intravenous line when the patient pushes a button. Although PCA dosing has been favorably compared to IM dosing in studies of physiological post-operative recovery, the psychological effects of giving patients moment to moment control over medication have not been examined. This project proposes to study sixty cholecystectomy patients, randomly assigned to either PCA or IM dosing for pain and will address the following issues related to the clinical usefulness of PCA dosing and the relationship between coping styles, pain and use of medication after surgery. The clinical usefulness of PCA dosing will be examined in two ways: First, psychological and physical recovery patterns of IM and PCA patients assessed during and one month after surgery will be compared. Second, the question of whether PCA dosing is contraindicated for some patients will be tested by comparing psychological and physical profiles of patients who do well on PCA and IM regimens, and by examining interactions between mode of dosing and individual difference variables such as coping style and previous experience with surgery. Analysis techniques will emphasize multiple regression derivations of the general linear model. Use of medication for pain under both IM and PCA dosing shows wide individual variation. This project will examine the influence psychological variables have on variation in medication use. Patient's preferred strategies for coping with pain and actual behavior in coping with pain will be assessed and related to measures of recovery and medication-use. In addition, current approaches to studying the mediating effect "having control" has on response to stress will be examined. Concepts of control as the trait of locus control and as specific coping abilities related to emotional control and active problem-solving will be assessed and related to use of medication and recovery under PCA and IM dosing regimens. Finally, patterns of medication use under PCA dosing will be analyzed with autocorrelation techniques to characterize styles of medication use and assess their relationship to surgical recovery and styles of coping with stress.